This invention relates to optical systems, and more particularly to integrated optical devices manufactured using a three-dimensional multi-layer technology.
Rapid, substantial improvements in telecommunications and networking have been made possible by advances in optical technology or photonics. A variety of optical devices are used to multiplex and de-multiplex optical signals onto fiber optic lines. Logical operations can also be performed using optical rather than electrical signals, although optical signal are often converted to electrical signals.
Splicing two optical fibers together provide a simple type of optical coupler that is still widely used. More complex optical couplers and attenuators have been made by a variety of methods. Usually these optical devices are not integrated with other optical devices, or are integrated with only a few other optical components. Optical technology is limited by a relatively low level of integration when compared to electronic devices with millions of integrated transistors.
Some optical devices may contain an optical waveguide formed by a layer of high-refractive-index material that is sandwiched between upper and lower layers of low-index material. The light is restricted to traveling in wave-guides formed in the high-index layer. However, this mostly-planar structure may not allow for cross-over of one waveguide by another. Light generally travels within the two dimensions of the sandwiched optical-guide layer.
Other components such as filters may be desirable, but are typically not integrated with the waveguides on the same substrate. Some type of hybrid, thick-film multi-substrate structure may be used which is much larger than an integrated, thin-film structure on one substrate.
What is desired is an integrated optical device, such as an optical power coupler or attenuator. An optical device formed by many layers of thin films on a single substrate is desirable. Waveguides formed by the thin films are desired to be integrated with optical filters that are also formed by the thin films integrated on the same substrate. A three-dimensional multi-layer optical device structure is desirable.